Dear Sankha Subhra Som Since in practical situations, the root password is often shared between 2 or more administrators. Hence to enforce control, root is restricted from logging in directly to the machine completely.
But how do you enforce that (using securetty u can specify secure terminals, but how do you enforce it so that only logins thru su are permitted) And does the statement "a secure machine has a boot loader password that doesnt work" also make sense? Regards Sankha